What ADV ring is better for Duel Blade and Paladin?

Aka
What ADV ring is better for Duel Blade?
What ADV ring is better for Paladin?

Critical.
Cruel.

The best ring for a Paladin depends on the situation.
Soloing-> Lilin's 3rd ring > Cruel > Lilin's 2nd ring > Critical
Party with crit buff-> Critical > Cruel > Lilin's 3rd ring

If you've got Lilin's 3rd ring, get the Critical Ring. If you don't, Cruel is a decent compromise.